FIELD
The instant invention relates to devices installed in a stream to protect downstream structures from damage by contaminants. The term stream is intended to include any fluid, whether normally flowing or flowing only by virtue of intermittent activity such as tidal activity or during flooding.
Downstream is defined as situated in or along a stream a distance from the devices of the instant invention in the direction of the flow. Upstream is defined similarly except that the direction is opposite that of the flow.
Contaminant is defined as any material, substance or object carried in or on a fluid other than the fluid itself.
Buoyant is defined to include the state of a contaminant where, by virtue of its displacement, it may be floating on the surface of the fluid, partly submerged, or completely submerged but not resting on the bed of a fluid channel.
Scour damage is defined as damage resulting from contaminants abrading a structure. Scour is also used in its dictionary definition, ie, to clear, dig, or remove by or as if by a powerful current or water.
Vortex-pair is defined as any pair of counter-rotating vortices generated by one or more vortex-generators.